WO2023195269A1

WO2023195269A1 - Blowing agent, foaming resin composition, polyurea resin foam, and production method for polyurea resin foam

Info

Publication number: WO2023195269A1
Application number: PCT/JP2023/007188
Authority: WO
Inventors: 裕貴川島; 和起河野
Original assignee: 三菱瓦斯化学株式会社
Priority date: 2022-04-06
Filing date: 2023-02-28
Publication date: 2023-10-12
Also published as: TW202405144A

Abstract

A blowing agent for obtaining a polyurea resin foam containing polyurea that has repeating units represented by general formula (I), said blowing agent including a reaction product (a2) of carbon dioxide and a cyclic amine compound (a1). (In formula (I), R1 is a divalent hydrocarbon group having a cyclic structure that may have a substituent, and R2 is a divalent hydrocarbon group that may have a substituent.)

Description

Foaming agent, foamable resin composition, polyurea resin foam, and method for producing polyurea resin foam

The present invention relates to a blowing agent, a foamable resin composition, a polyurea resin foam, and a method for producing a polyurea resin foam.

Polyurea resin is a resin compound with urea bonds produced by a chemical reaction between polyisocyanate and polyamine, and has properties such as waterproofness, chemical resistance, abrasion resistance, heat resistance, corrosion resistance, quick drying, and environmental safety. Are better. Polyurea resins are widely used in various fields such as synthetic leather, artificial leather, adhesives, and paints.
Further, it is also being considered to provide polyurea resin with functions such as heat insulation, sound insulation, and lightness by foaming the polyurea resin.
Examples of techniques related to polyurea resin foams include those described in Patent Documents 1 and 2.

Patent Document 1 discloses that a polyurea foam having an isocyanurate structure and an isocyanurate rate of 25 to 50% has excellent flame retardancy and shape retention during combustion, and has excellent flame retardancy and shape retention during combustion, and is resistant to aging in a moist heat environment. It is described that it can suppress deterioration, has excellent adhesion to adherends during coating, is resistant to cracking even when exposed to flame, and is difficult to cause carbonization to progress from the surface to the deep part due to exposure to flame.

Patent Document 2 describes an isocyanate component; an isocyanate-reactive component; a catalyst selected from a foaming catalyst and/or a gelling catalyst and comprising N-(3-dimethylaminopropyl)-N,N-diisopropanolamine; It is described that a composition comprising: an amine component; the total amount of the amine component being from 0.05% to 0.50% by weight can produce polyurea foams with reduced formaldehyde emissions.

Patent No. 6925554 JP2019-206712A

Conventionally, a blowing agent is required to obtain a foam, and in order to obtain higher foamability, a large amount of foam needs to be used and discarded. On the other hand, polyamines used as raw materials for polyurea resins can absorb carbon dioxide, and therefore are useful as materials for absorbing waste carbon dioxide.
The present invention provides a novel method for producing a polyurea resin foam that can reduce environmental impact and has improved foamability, a blowing agent and a foamable resin composition used in the production method, and a polyurea resin foam that has improved foamability. The present invention provides a resin foam.

The present inventors have made extensive studies to solve the above problems. As a result, by using the reaction product of a cyclic amine compound and carbon dioxide as a blowing agent to obtain polyurea resin foam, it is possible to reduce the amount of conventional blowing agents that have a large environmental impact, and It has been found that the environmental impact during the production of resin foam can be reduced. Furthermore, it has been found that by using the above-mentioned reactant as a blowing agent for obtaining a polyurea resin foam, the foamability of the resulting polyurea resin foam can be improved. In this way, the present inventors completed the present invention. Furthermore, since the reactant can be produced by absorbing carbon dioxide in the environment, it also contributes to reducing environmental load.

That is, according to the present invention, the following blowing agent, foamable resin composition, polyurea resin foam, and method for producing a polyurea resin foam are provided.

[1] A blowing agent for obtaining a polyurea resin foam containing polyurea having a repeating unit represented by the following general formula (I),
A blowing agent containing a reaction product (a2) of a cyclic amine compound (a1) and carbon dioxide.

(In formula (I), R ¹ is a divalent hydrocarbon group having a cyclic structure that may have a substituent, and R ² is a divalent hydrocarbon group that may have a substituent. It is a hydrogen group.)
[2] When the cyclic amine compound (a1) is allowed to stand for one week in an air environment of 23°C and 50% RH, the mass increase rate of the cyclic amine compound (a1) calculated by the following formula is 10 mass % or more and 50% by mass or less, the blowing agent according to [1] above.
Mass increase rate [mass%] of cyclic amine compound (a1) = 100 x mass increase amount (g) of cyclic amine compound (a1) / (mass (g) of cyclic amine compound (a1) + cyclic amine compound (a1) mass increase (g))
[3] The blowing agent according to [1] or [2] above, wherein the cyclic amine compound (a1) has an amino group bonded to a primary carbon atom.
[4] The blowing agent according to any one of [1] to [3] above, wherein the cyclic structure of the cyclic amine compound (a1) includes at least one type selected from a 5-membered ring and a 6-membered ring.
[5] The blowing agent according to any one of [1] to [4] above, wherein the number of amino groups in the cyclic amine compound (a1) is 2 or more and 6 or less.
[6] The cyclic amine compound (a1) contains at least one selected from the group consisting of xylylenediamine and its derivatives, bis(aminomethyl)cyclohexane and its derivatives, limonenediamine and its derivatives, and isophoronediamine and its derivatives. The blowing agent according to any one of [1] to [5] above.
[7] The blowing agent according to any one of [1] to [6] above, wherein the amount of water in the reactant (a2) is 50% by mass or less.
[8] The above-mentioned [1] to [2], wherein the molar ratio of the moiety derived from the cyclic amine compound (a1) and the moiety derived from carbon dioxide [cyclic amine compound (a1)/carbon dioxide] is 70/30 to 30/70. 7].
[9] The blowing agent according to any one of [1] to [8] above, wherein the content of the repeating unit represented by the general formula (I) in the polyurea is 50% by mass or more.
[10] Produced by a method in which the cyclic amine compound (a1) is brought into contact with a gas having a carbon dioxide concentration of 0.01% by volume or more and 10% by volume or less, and the cyclic amine compound (a1) and carbon dioxide are reacted. The blowing agent according to any one of [1] to [9] above.
[11] A foamable resin composition for obtaining a polyurea resin foam, comprising the blowing agent (A) according to any one of [1] to [10] above, a polyisocyanate compound (B), A foamable resin composition containing.
[12] The foamable resin composition according to [11], wherein the polyisocyanate compound (B) includes a compound having two or more isocyanate groups.
[13] The foamable resin composition according to [11] or [12], wherein the content of a blowing agent other than the blowing agent (A) is 5% by mass or less.
[14] The content of the blowing agent (A) in the foamable resin composition is determined by the ratio of the number of amino groups in the blowing agent (A) to the number of isocyanate groups in the polyisocyanate compound (B) (the number of amino groups). / number of isocyanate groups) is 0.5 or more and 1.5 or less, the foamable resin composition according to any one of [11] to [13].
[15] The polyisocyanate compound (B) is at least one selected from the group consisting of isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HDI), and 4,4'-diphenylmethane diisocyanate (MDI). , the foamable resin composition according to any one of [11] to [14] above.
[12] A polyurea resin foam obtained by foam-molding the foamable resin composition according to any one of [11] to [15] above.
[13] A method for producing a polyurea resin foam, comprising the step of foam-molding the foamable resin composition according to any one of [11] to [15] above.

According to the present invention, there is provided a novel method for producing a polyurea resin foam that reduces environmental impact and has improved foamability, a blowing agent and a foamable resin composition used in the production method, and an improved foamability. A polyurea resin foam can be provided.

A mode for carrying out the present invention (hereinafter simply referred to as "this embodiment") will be described in detail. The present embodiment below is an illustration for explaining the present invention, and does not limit the content of the present invention. The present invention can be implemented with appropriate modifications within the scope of its gist. In this embodiment, the preferred regulations can be arbitrarily adopted, and a combination of preferred regulations can be said to be more preferable. In the present embodiment, the description “XX to YY” means “XX or more and YY or less”.

[Blowing agent (Blowing agent (A))]
The blowing agent of the present invention (the blowing agent explained in this section is the same as the blowing agent (A) contained in the foamable resin composition described below) is a repeating unit represented by the following general formula (I). This is a blowing agent for obtaining a polyurea resin foam containing a polyurea having the following properties, and the blowing agent contains a reaction product (a2) of a cyclic amine compound (a1) and carbon dioxide.

(In formula (I), R ¹ is a divalent hydrocarbon group having a cyclic structure that may have a substituent, and R ² is a divalent hydrocarbon group that may have a substituent. It is a hydrogen group.)
According to the blowing agent of the present invention, by using the reaction product (a2) of a cyclic amine compound (a1) and carbon dioxide as a blowing agent for molding a polyurea resin foam, the environmental load can be reduced. At the same time, a polyurea resin foam with improved foamability can be obtained.

According to the present invention, it is possible to obtain a polyurea resin foam containing a reaction product (a2) of a cyclic amine compound (a1) and carbon dioxide and having improved foamability. Although the reason is not certain, it is thought to be as follows.
Since the cyclic amine compound (a1) has a relatively high ability to retain carbon dioxide and low water absorption, the cyclic amine compound and carbon dioxide are generated by heating when molding the resin. At this time, since a sufficient amount of carbon dioxide contributes to foaming, it is thought that a polyurea resin foam with improved foaming properties can be obtained. Further, since the cyclic amine compound (a1) has a high ability to retain carbon dioxide, it can absorb carbon dioxide in the environment, and the use of other blowing agents can also be reduced, so that the environmental load can also be reduced.

The cyclic amine compound (a1) preferably has an amino group bonded to a primary carbon atom from the viewpoint of further improving reactivity with carbon dioxide and foaming properties. It is thought that such an amino group has little steric hindrance and easily absorbs carbon dioxide.
The cyclic amine compound (a1) is an amine compound having a cyclic structure. The cyclic structure of the cyclic amine compound (a1) includes, for example, an alicyclic hydrocarbon structure, an aromatic hydrocarbon structure, a heterocyclic structure containing a heteroatom in the ring, etc., and has a high reactivity with carbon dioxide. And from the viewpoint of further improving foaming properties, it is preferable that at least one structure selected from an alicyclic hydrocarbon structure and an aromatic hydrocarbon structure is included, and it is more preferable that an alicyclic hydrocarbon structure is included.
Here, in this embodiment, the alicyclic hydrocarbon structure refers to a cyclic structure consisting of saturated or unsaturated carbon and hydrogen that does not have aromaticity, and is a heterocyclic structure containing a heteroatom in the ring. Formula structures are removed. Further, the term "heterocyclic structure" refers to a ring structure containing a heteroatom among the atoms constituting the ring.
The cyclic amine compound (a1) may be a cis form, a trans form, or a mixture of a cis form and a trans form.

The cyclic structure of the cyclic amine compound (a1) preferably contains at least one type selected from a 5-membered ring and a 6-membered ring, from the viewpoint of further improving the reactivity with carbon dioxide and foaming property. It is more preferable to include.
Moreover, it is preferable that the cyclic amine compound (a1) has one cyclic structure from the viewpoint of further improving the reactivity with carbon dioxide and the foaming property. That is, the cyclic amine compound (a1) is preferably a monocyclic compound.
Examples of the alicyclic hydrocarbon structure of the cyclic amine compound (a1) include a cyclopropane ring, a cyclobutane ring, a cyclopentane ring, a cyclohexane ring, a cycloheptane ring, and a cyclooctane ring. Among the above ring structures, a cyclopentane ring and a cyclohexane ring are preferred, a cyclohexane ring is more preferred, and a 1,3-substituted cyclohexane ring is even more preferred.

The number of amino groups in the cyclic amine compound (a1) is preferably 2 or more, and preferably 6 or less, more preferably 4, from the viewpoint of further improving the reactivity with carbon dioxide, curability, and foamability. The number is preferably 3 or less, and even more preferably 2.
In addition, as the amino group, an amino group having a nitrogen-hydrogen bond is preferable from the viewpoint of further improving the reactivity with carbon dioxide, curability, and foaming property, and is composed of a primary amino group and a secondary amino group. At least one type of amino group selected from the group is more preferred, and a primary amino group is even more preferred.

The cyclic amine compound (a1) is preferably selected from o-xylylenediamine and its derivatives, m-xylylenediamine and its derivatives, p-xylylenediamine and its derivatives, and the compound represented by the following formula (II). There is at least one type of

In the above formula (II), R ³ to R ⁶ are each independently a hydrogen atom, or a carbon which may have at least one substituent selected from an amino group, a cyano group, a phenyl group, a hydroxyl group, and a carboxy group. Represents a hydrocarbon group having a number of 1 or more and 10 or less, R ⁷ to R ¹² each independently represents a hydrogen atom or a hydrocarbon group having 1 or more and 4 or less carbon atoms, and x and y each independently represent an integer of 0 or more and 6 or less , x+y is 1 or more and 6 or less, p and q are each independently an integer of 0 or more and 4 or less, and at least one of p and q is 1 or more.

R ³ to R ⁶ each independently have a hydrogen atom or a carbon number of 1 to 10, which may have at least one substituent selected from an amino group, a cyano group, a phenyl group, a hydroxyl group, and a carboxy group. is a hydrocarbon group, preferably a hydrogen atom, or a hydrocarbon group having 1 to 10 carbon atoms that may have at least one substituent selected from an amino group, a cyano group, and a phenyl group, More preferably a hydrogen atom, or an alkyl group having 1 to 4 carbon atoms that may have at least one substituent selected from an amino group, a cyano group, and a phenyl group, and even more preferably a hydrogen atom, or An alkyl group having 1 to 4 carbon atoms that may have at least one substituent selected from an amino group and a cyano group, and even more preferably a hydrogen atom, or a hydrogen atom, or an amino group and a cyano group. It is an alkyl group having 2 or more and 4 or less carbon atoms which may have at least one substituent, and even more preferably a hydrogen atom.
The number of carbon atoms in the hydrocarbon groups R ³ to R ⁶ is each independently 1 or more, preferably 2 or more. And it is 10 or less, preferably 5 or less, more preferably 4 or less, and still more preferably 3 or less.

R ⁷ to R ¹² each independently represent a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms, preferably a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and more preferably a hydrogen atom or a hydrocarbon group having 1 to 4 carbon atoms. It is an alkyl group having 1 to 3 carbon atoms, more preferably a hydrogen atom or a methyl group, and even more preferably a hydrogen atom.
The number of carbon atoms in the hydrocarbon groups R ⁷ to R ¹² is each independently from 1 to 4, preferably 1 or 2, and more preferably 1.

p and q are each independently 0 or more, preferably 1 or more, and 4 or less, preferably 2 or less, and more preferably 1. However, at least one of p and q is 1 or more.

x and y each independently represent an integer of 0 or more and 6 or less, and x+y is 1 or more and 6 or less. From the viewpoint of further improving the carbon dioxide absorption amount and foamability, x+y is preferably 2 or more, more preferably 3 or more, and still more preferably 4 or more, and from the viewpoint of further improving the carbon dioxide absorption amount and foamability, Preferably it is 5 or less, more preferably 4. That is, the alicyclic hydrocarbon structure is preferably a 5-membered ring or a 6-membered ring, more preferably a 6-membered ring. When x+y is 4, preferably x is 1 and y is 3.

The cyclic amine compound (a1) is xylylenediamine and its derivatives, bis(aminomethyl)cyclohexane and its derivatives, limonenediamine and its derivatives, from the viewpoint of further improving the reactivity with carbon dioxide, curability and foaming property. It preferably contains at least one selected from the group consisting of isophorone diamine and its derivatives, 2,5-bisaminomethylfuran and its derivatives, and 2,5-bis(aminomethyl)tetrahydrofuran and its derivatives, and xylylene diamine and its derivatives are preferably included. More preferably, it contains at least one selected from the group consisting of amines and derivatives thereof, bis(aminomethyl)cyclohexane and derivatives thereof, limonenediamine and derivatives thereof, and isophoronediamine and derivatives thereof, xylylenediamine and derivatives thereof, More preferred is at least one selected from the group consisting of bis(aminomethyl)cyclohexane and its derivatives, and isophoronediamine and its derivatives, and more preferably from the group consisting of xylylenediamine and its derivatives, and bis(aminomethyl)cyclohexane and its derivatives. It is even more preferable to include at least one selected one.
Examples of the cyclic amine compound (a1) include xylylene diamine and its derivatives, bis(aminomethyl)cyclohexane and its derivatives, limonenediamine and its derivatives, from the viewpoint of further improving the reactivity with carbon dioxide, curability, and foaming property. , isophoronediamine and its derivatives, 2,5-bisaminomethylfuran and its derivatives, and 2,5-bis(aminomethyl)tetrahydrofuran and its derivatives, and xylylenediamine and At least one selected from the group consisting of derivatives thereof, bis(aminomethyl)cyclohexane and its derivatives, limonenediamine and its derivatives, and isophoronediamine and its derivatives is more preferable, and xylylenediamine and its derivatives, bis(aminomethyl) At least one selected from the group consisting of cyclohexane and its derivatives, and isophoronediamine and its derivatives is more preferred, and at least one selected from the group consisting of xylylene diamine and its derivatives, and bis(aminomethyl)cyclohexane and its derivatives. is even more preferred.

Examples of xylylene diamine and its derivatives include at least one selected from the group consisting of o-xylylene diamine and its derivatives, m-xylylene diamine and its derivatives, and p-xylylene diamine and its derivatives, and preferably is at least one selected from the group consisting of m-xylylene diamine and its derivatives, p-xylylene diamine and its derivatives, and more preferably m-xylylene diamine and its derivatives.
Examples of bis(aminomethyl)cyclohexane and its derivatives include 1,3-bis(aminomethyl)cyclohexane and its derivatives, 1,4-bis(aminomethyl)cyclohexane and its derivatives, and trans-1,4-bis(aminomethyl)cyclohexane and its derivatives. At least one selected from the group consisting of methyl)cyclohexane and its derivatives is mentioned, and 1,3-bis(aminomethyl)cyclohexane and its derivatives are preferred.

Among these, the cyclic amine compound (a1) is preferably m-xylylenediamine and its derivatives, and 1,3-bis(aminomethyl) from the viewpoint of further improving reactivity with carbon dioxide and foaming property. It is at least one selected from the group consisting of cyclohexane and its derivatives, and 1,3-bis(aminomethyl)cyclohexane and its derivatives are more preferred.

Here, as the above-mentioned various amine derivatives, for example, at least one of the hydrogen atoms of the amino group has at least one substituent selected from the group consisting of an amino group, a cyano group, and a phenyl group. a hydrocarbon group having 1 to 10 carbon atoms, preferably an alkyl group having 1 to 4 carbon atoms, which may have at least one substituent selected from the group consisting of an amino group, a cyano group, and a phenyl group; group, more preferably an alkyl group having 1 to 4 carbon atoms which may have at least one substituent selected from the group consisting of an amino group and a cyano group, and even more preferably a group consisting of an amino group and a cyano group. Examples include compounds substituted with an alkyl group having 2 or more and 4 or less carbon atoms, which may have at least one substituent selected from the following.
Further, as the derivatives of the above-mentioned various amines, for example, at least a part of the hydrogen atoms in the cyclic structure are hydrocarbon groups having 1 to 4 carbon atoms, preferably alkyl groups having 1 to 3 carbon atoms, and more preferably Examples include compounds substituted with a methyl group or an ethyl group, more preferably a methyl group.
As mentioned above, the cyclic amine compound (a1) is preferably an amine (primary amine). That is, the cyclic amine compound (a1) is preferably at least one selected from the group consisting of xylylene diamine and bis(aminomethyl)cyclohexane from the viewpoint of further improving reactivity with carbon dioxide and foaming properties. .
Examples of the xylylene diamine include at least one selected from the group consisting of o-xylylene diamine, m-xylylene diamine and p-xylylene diamine, preferably m-xylylene diamine and p-xylylene diamine. At least one selected from the group consisting of m-xylylenediamine, and more preferably m-xylylenediamine.
Bis(aminomethyl)cyclohexane is selected from the group consisting of 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, and trans-1,4-bis(aminomethyl)cyclohexane. 1,3-bis(aminomethyl)cyclohexane is preferred.

Among these, the cyclic amine compound (a1) is preferably a group consisting of m-xylylene diamine and 1,3-bis(aminomethyl)cyclohexane from the viewpoint of further improving reactivity with carbon dioxide and foaming property. 1,3-bis(aminomethyl)cyclohexane is more preferred.

These cyclic amine compounds (a1) can be used alone or in combination of two or more.

The maximum carbon dioxide dissociation temperature of the cyclic amine compound (a1), measured by the following method, is preferably 200°C or less, more preferably The temperature is 180°C or lower, more preferably 160°C or lower, even more preferably 150°C or lower, even more preferably 140°C or lower, even more preferably 135°C or lower, even more preferably 130°C or lower. below ℃. The lower limit of the carbon dioxide maximum dissociation temperature is not particularly limited, but is, for example, 40°C or higher.
(Method)
The cyclic amine compound (a1) that has absorbed carbon dioxide is heated from 23°C to 250°C at a heating rate of 10°C/min, and the temperature at which the amount of heat absorbed due to the desorption of carbon dioxide is maximum is measured. The temperature is taken as the carbon dioxide maximum dissociation temperature. Here, the cyclic amine compound (a1) that has absorbed carbon dioxide can be prepared, for example, by leaving 5 mmol of the cyclic amine compound (a1) in air at 23° C. and 50% RH for 24 hours.

The acid dissociation constant (pKa) of the cyclic amine compound (a1) is preferably 8.0 or more, more preferably 8.5 or more, and even more preferably is 9.0 or higher. From the viewpoint of improving carbon dioxide dissociation properties and further improving foamability, it is preferably 12.0 or less, more preferably 11.5 or less, and still more preferably 11.0 or less.
The acid dissociation constant of the cyclic amine compound (a1) is a value determined by the following measuring method based on the acid-base suitability method.
(1) Dissolve 0.2 g of cyclic amine compound (a1) in 30 mL of purified water.
(2) By titrating the solution obtained in (1) above with a 0.1 N perchloric acid-acetic acid solution using an automatic potentiometric titrator (for example, AT-610, manufactured by Kyoto Electronics Co., Ltd.). Calculate the acid dissociation constant (pKa).
Note that the temperature during measurement is 25±2°C.

The molecular weight of the cyclic amine compound (a1) is preferably 110 or more, more preferably 120 or more, and still more preferably 130 or more, from the viewpoint of suppressing weight loss during heat treatment when dissociating carbon dioxide. . From the viewpoint of further improving carbon dioxide absorption and foamability, it is preferably 250 or less, more preferably 200 or less, and even more preferably 180 or less.

The maximum endothermic temperature of the cyclic amine compound (a1) measured by the following method is preferably 130°C or higher, more preferably 140°C from the viewpoint of suppressing weight loss during heat treatment when dissociating carbon dioxide. The temperature is above, and more preferably 150°C or above. From the viewpoint of further improving carbon dioxide absorption and foamability, the temperature is preferably 260°C or lower, more preferably 230°C or lower, even more preferably 210°C or lower, even more preferably 190°C or lower. be.
(Method)
The cyclic amine compound (a1) is heated from 23°C to 350°C at a heating rate of 10°C/min, the temperature at which the amount of heat absorbed due to the volatilization of the amine compound (a1) is maximum is measured, and this temperature is determined as the temperature of the amine compound. (a1) is the maximum endothermic temperature.

The amine value of the cyclic amine compound (a1) is preferably 400 mgKOH/g or more, more preferably 500 mgKOH/g or more, and even more preferably 600 mgKOH/g, from the viewpoint of further improving carbon dioxide absorption and foaming properties. It is more preferably 650 mgKOH/g or more, and even more preferably 700 mgKOH/g or more. And preferably it is 1500 mgKOH/g or less, more preferably 1400 mgKOH/g or less, still more preferably 1300 mgKOH/g or less, even more preferably 1100 mgKOH/g or less, even more preferably 1000 mgKOH/g or less, Even more preferably it is 850 mgKOH/g or less. The amine value indicates the amount of amine in the compound, and refers to the number of mg of potassium hydroxide (KOH) equivalent to the acid required to neutralize 1 g of the compound.
The amine value can be measured by the following method according to JIS K7237-1995.
(1) Dissolve 0.1 g of cyclic amine compound (a1) in 20 mL of acetic acid.
(2) By titrating the solution obtained in (1) above with a 0.1 N perchloric acid-acetic acid solution using an automatic potentiometric titrator (for example, AT-610, manufactured by Kyoto Electronics Co., Ltd.). Calculate the amine value.

When the cyclic amine compound (a1) is left standing for one week in an air environment of 23 ° C. and 50% RH, the mass increase rate of the cyclic amine compound (a1) calculated by the following formula further improves foaming properties. From this point of view, it is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 18% by mass or more, even more preferably 20% by mass or more, even more preferably 23% by mass. That's all. The amount is preferably 50% by mass or less, more preferably 45% by mass or less, even more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 28% by mass or less. It is.
Mass increase rate [mass%] of cyclic amine compound (a1) = 100 x mass increase amount (g) of cyclic amine compound (a1) / (mass (g) of cyclic amine compound (a1) + cyclic amine compound (a1) mass increase (g))
The mass increase rate of the cyclic amine compound (a1) can be specifically measured by the method described in Examples.

The blowing agent of the present invention can be obtained, for example, by bringing the cyclic amine compound (a1) into contact with a gas containing carbon dioxide and reacting the cyclic amine compound (a1) with carbon dioxide. That is, in a preferred method for producing a blowing agent of the present invention, the cyclic amine compound (a1) is brought into contact with a gas containing carbon dioxide to cause the cyclic amine compound (a1) and carbon dioxide to react.

The gas containing carbon dioxide may be carbon dioxide alone or a mixture of carbon dioxide and an inert gas. It is convenient and preferable to use air as the gas containing carbon dioxide. Here, the term "inert gas" refers to a gas that does not affect the reaction when obtaining a polyurea resin foam, which will be described later.
A step of reacting the cyclic amine compound (a1) with carbon dioxide to obtain a reactant (a2) by contacting the gas containing carbon dioxide with a carbon dioxide concentration of 0.01% by volume or more and 10% by volume or less. It is preferable to further include. That is, the blowing agent of the present invention allows the cyclic amine compound (a1) to react with carbon dioxide by bringing the cyclic amine compound (a1) into contact with a gas having a carbon dioxide concentration of 0.01% by volume or more and 10% by volume or less. Preferably, the blowing agent is a blowing agent produced by a method.
The carbon dioxide concentration is preferably 0.01 volume% or more, more preferably 0.02 volume% or more, still more preferably 0.03 volume% or more, and preferably 10 volume% or less. It is more preferably 5% by volume or less, still more preferably 1% by volume or less, even more preferably 0.5% by volume or less, even more preferably 0.1% by volume or less. Moreover, it is more preferable that the gas having a carbon dioxide concentration of 0.01% by volume or more and 10% by volume or less is air.

There are no restrictions on the method of bringing the cyclic amine compound (a1) into contact with a gas containing carbon dioxide, but the cyclic amine compound (a1) may be brought into contact with a gas containing carbon dioxide at 30°C or lower while stirring or shaking. It is preferable to store the product until the mass increase rate falls within a desired range. There is no limit to the pressure at which the cyclic amine compound (a1) is brought into contact with a gas containing carbon dioxide, but it is preferably stored under atmospheric pressure or increased pressure, and more preferably stored under atmospheric pressure.
The time of contact with the gas containing carbon dioxide may be adjusted according to the temperature, pressure, and amount of carbon dioxide contained in the gas as shown above, but air is used as the gas containing carbon dioxide and stored under atmospheric pressure. In this case, the time of contact with the gas containing carbon dioxide is preferably 1 hour or more, more preferably 1 day or more, still more preferably 5 days or more, even more preferably 10 days or more. , even more preferably 15 days or more, even more preferably 30 days or more. Although there is no upper limit, it is preferably 100 days or less.

The reaction product (a2) of the cyclic amine compound (a1) and carbon dioxide preferably contains at least one selected from carbamic acid, carbamate, carbonate, and hydrogen carbonate.

Since the blowing agent of the present invention is a reaction product (a2) of a cyclic amine compound (a1) and carbon dioxide, it forms a salt as described above, but the cyclic amine compound (a1) contained in the blowing agent The molar ratio of the derived portion and the carbon dioxide derived portion [amine compound (a1)/carbon dioxide] is preferably 70/30 to 30/70, more preferably 60/40 to 40/60, and Preferably it is 55/45 to 45/55.
The water content in the reactant (a2) is preferably 50% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less, even more preferably 5% by mass or less. be. When the moisture content is within the above range, foaming properties can be improved.
As described above, the blowing agent of the present invention can be obtained by contacting the cyclic amine compound (a1) with a gas containing carbon dioxide, but it is preferable not to add water at that time.

The blowing agent of the present invention is a blowing agent for obtaining a polyurea resin foam containing polyurea having a repeating unit represented by the following general formula (I).

(In formula (I), R ¹ is a divalent hydrocarbon group having a cyclic structure that may have a substituent, and R ² is a divalent hydrocarbon group that may have a substituent. It is a hydrogen group.)

R ¹ is a divalent hydrocarbon group having a cyclic structure that may have a substituent, and is a hydrocarbon group derived from the cyclic amine compound (a1). That is, R ¹ is a divalent group obtained by removing two amino groups from the above-mentioned cyclic amine compound (a1), and the preferred amine compound forming R ¹ is also the same as the above-mentioned cyclic amine compound (a1). .
R ¹ is preferably a hydrocarbon group having 6 to 20 carbon atoms, more preferably a hydrocarbon group having 8 to 10 carbon atoms. Moreover, it is preferable that it consists only of carbon and hydrogen. Among these, at least one type selected from the group consisting of a xylylene group and a cyclohexanediylbis(methylene) group is preferred.
Examples of the xylylene group include at least one selected from the group consisting of o-xylylene group, m-xylylene group and p-xylylene group, preferably selected from the group consisting of m-xylylene group and p-xylylene group. It is at least one type, and m-xylylene group is more preferable.
The cyclohexanediylbis(methylene) group is preferably a cyclohexane-1,3-diylbis(methylene) group.
R ² is a divalent hydrocarbon group which may have a substituent, and is a hydrocarbon group derived from the polyisocyanate compound (B). That is, R ² is a divalent group obtained by removing two isocyanate groups from the polyisocyanate compound (B) described below, and a preferable polyisocyanate compound forming R ² is also the same as the polyisocyanate compound (B) described below. be.
R ² is preferably a hydrocarbon group having 6 to 20 carbon atoms, more preferably a hydrocarbon group having 6 to 13 carbon atoms. Moreover, it is preferable that it consists only of carbon and hydrogen. Among these, it is preferably selected from the group consisting of 1,6-hexamethylene group, 4,4'-methylene diphenyl group, and 3,3,5-trimethylcyclohexane-1,3-diyl (3-methylene) group. At least one kind.
Note that R ¹ and R ² may each be composed of one type of divalent hydrocarbon group, or may contain a plurality of divalent hydrocarbon groups.

The polyurea having a repeating unit represented by the general formula (I) may have a structure other than the repeating unit represented by the general formula (I), and may have a branched structure or a crosslinked structure. Good too. The content of the repeating unit represented by the general formula (I) in the polyurea is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, More preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 98% by mass or more, still more preferably 99% by mass, Preferably it is 100% by mass or less. The polyurea having the repeating unit represented by the general formula (I) may consist only of the repeating unit represented by the general formula (I).
The total of urea bonds and carbon atoms in the main chain of the polyurea having the repeating unit represented by the general formula (I) is preferably 50% or more, more preferably 60% or more, in terms of the number of atoms, More preferably 70% or more, still more preferably 80% or more, still more preferably 90% or more, even more preferably 95% or more, still more preferably 98% or more, still more preferably 99% or more, preferably 100% or less. The main chain of the polyurea having the repeating unit represented by the general formula (I) may consist only of urea bonds and carbon atoms.

[Foamable resin composition]
The foamable resin composition of the present invention is a foamable resin composition for obtaining a polyurea resin foam, and includes the foaming agent (A) and a polyisocyanate compound (B). It is a thing. That is, the foamable resin composition of the present invention is a foamable resin composition for obtaining a polyurea resin foam containing polyurea having a repeating unit represented by the general formula (I), This is a foamable resin composition containing a blowing agent (A) containing a reaction product (a2) of compound (a1) and carbon dioxide, and a polyisocyanate compound (B).
According to the foamable resin composition of the present invention, a polyurea resin foam with improved foamability can be obtained.

The blowing agent (A) contained in the foamable resin composition of the present invention is the same as the blowing agent explained in the section of [Blowing agent (Blowing agent (A))] above.
The foamable resin composition of the present invention may contain a blowing agent other than the blowing agent (A), but it is preferable that it is substantially not contained. The content of the blowing agent other than the blowing agent (A) in the foamable resin composition is preferably 5% by mass or less, more preferably 3% by mass or less, still more preferably 1% by mass or less, It is even more preferably 0.5% by mass or less, even more preferably 0.1% by mass or less, even more preferably 0% by mass, and even more preferably not contained.
Examples of blowing agents other than the blowing agent (A) include fluorocarbon-based halogen-containing hydrocarbons such as chlorofluorocarbons and fluorocarbons; alicyclic hydrocarbons such as cyclopentane; dinitropentamethylenetetramine, azodicarbonamide, p , p'-oxybisbenzenesulfonyl hydrazide, and other organic blowing agents; and inorganic blowing agents such as sodium hydrogen carbonate.

The content of the blowing agent (A) in the foamable resin composition is determined by the ratio of the number of amino groups in the blowing agent (A) to the number of isocyanate groups in the polyisocyanate compound (B) (number of amino groups/number of isocyanate groups). , preferably 0.5 or more and 1.5 or less. The ratio of the number of amino groups in the foaming agent (A) to the number of isocyanate groups in the polyisocyanate compound (B) (number of amino groups/number of isocyanate groups) is preferably 0.5 or more from the viewpoint of improving foamability. , more preferably 0.6 or more, still more preferably 0.7 or more, even more preferably 0.8 or more, even more preferably 0.9 or more. From the same viewpoint, it is preferably 1.5 or less, more preferably 1.4 or less, even more preferably 1.3 or less, even more preferably 1.2 or less, even more preferably 1 .1 or less.

<Polyisocyanate compound (B)>
The polyisocyanate compound (B) is not particularly limited as long as it contains a compound having two or more isocyanate groups, and conventionally known compounds can be used. The polyisocyanate compound (A) is preferably a compound having two or more isocyanate groups.
Examples of diisocyanate compounds having two isocyanate groups include 1,6-hexamethylene diisocyanate (HDI), 2,2,4-trimethylhexamethylene diisocyanate, methylene diisocyanate, isopropylene diisocyanate, lysine diisocyanate, lysine diisocyanate methyl ester, Aliphatic isocyanate compounds such as 1,5-octylene diisocyanate; 4,4'-dicyclohexylmethane diisocyanate, isophorone diisocyanate (IPDI), norbornene diisocyanate, hydrogenated tolylene diisocyanate, methylcyclohexane diisocyanate, isopropylidene bis(4-cyclohexyl isocyanate) ), alicyclic isocyanate compounds such as dimer acid diisocyanate; 2,4- or 2,6-tolylene diisocyanate (TDI), 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate, p- Or aromatic isocyanate compounds such as m-xylylene diisocyanate (XDI), toridine diisocyanate, p-phenylene diisocyanate, diphenyl ether diisocyanate, diphenylsulfone diisocyanate, dianisidine diisocyanate, and tetramethyl-m-xylylene diisocyanate.
Examples of isocyanate compounds having three or more isocyanate groups include triphenylmethane triisocyanate, triisocyanate phenylthiophosphate, polymethylene polyphenylene polyisocyanate (polymeric MDI), isocyanurate modified products that are trimers of HDI and TDI, and biuret modified products. Examples include the body.
The isocyanate compound (B) can be used alone or in combination of two or more.

Among these, diisocyanates having two isocyanate groups are preferable as the polyisocyanate compound (B), such as isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HDI), and 4,4'-diphenylmethane diisocyanate (MDI). is more preferred, isophorone diisocyanate (IPDI) and 1,6-hexamethylene diisocyanate (HDI) are even more preferred, and isophorone diisocyanate (IPDI) is even more preferred. That is, the polyisocyanate compound (B) is more preferably at least one selected from the group consisting of isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HDI), and 4,4'-diphenylmethane diisocyanate (MDI). , isophorone diisocyanate (IPDI), and 1,6-hexamethylene diisocyanate (HDI), and isophorone diisocyanate (IPDI) is even more preferred.

The foamable resin composition further contains fillers, modifying components such as plasticizers, flow adjusting components such as thixotropic agents, pigments, leveling agents, tackifiers, elastomer fine particles, curing accelerators, foam stabilizers, Other components such as chemical blowing agents may be included depending on the application.
Moreover, although the foamable resin composition may contain a solvent, it is preferable that the foamable resin composition does not substantially contain the solvent. Since it does not contain a solvent, it is highly environmentally friendly and can be easily obtained as a foam.
However, from the viewpoint of effectively obtaining the effects of the present invention, the total content of the blowing agent (A) and the polyisocyanate compound (B) in the foamable resin composition is the same as that contained in the foamable resin composition according to the present invention. When the total solid content is 100% by mass, it is preferably 50% by mass or more, more preferably 60% by mass or more, still more preferably 70% by mass or more, still more preferably 80% by mass or more, More preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 98% by mass or more, still more preferably 99% by mass or more, and from the same point of view, preferably 100% by mass. It is as follows.

<Method for preparing foamable resin composition>
There are no particular restrictions on the method for preparing the foamable resin composition, and it can be produced by mixing the foaming agent (A), the polyisocyanate compound (B), and other components as necessary using known methods and equipment. can.

[Polyurea resin foam and method for producing polyurea resin foam]
The polyurea resin foam of the present invention is formed by foam-molding the foamable resin composition according to the present invention described above. Therefore, the polyurea resin foam of the present invention contains polyurea having a repeating unit represented by the general formula (I). The polyurea having the repeating unit represented by the general formula (I) contained in the polyurea resin foam of the present invention is the same as that explained in the section of [Blowing agent (Blowing agent (A))] above. The preferred ranges are also the same.
The method for producing the polyurea resin foam of the present invention is not limited as long as it is formed by foam molding the foamable resin composition, but the preferred method for producing the polyurea resin foam is It includes a step of foam-molding the resin composition.

In the step of foaming the foamable resin composition, for example, by heating the foamable resin composition, the amine compound (a1) and carbon dioxide are generated from the reactant (a2) (foaming agent (A)), and carbon dioxide is generated. While foaming the foamable resin composition with carbon, the foamable resin composition is cured by the reaction of the generated amine compound (a1) and polyisocyanate compound (B). A polyurea resin foam can be obtained by such a method.

The heating temperature and heating time in the step of foaming the foamable resin composition can be selected as appropriate, but from the viewpoint of reaction rate, productivity, and prevention of decomposition of raw materials, etc., it is preferably 50 to 250 ° C., and more preferably. is 100 to 200°C, more preferably 120 to 180°C. The reaction time is preferably 10 minutes to 12 hours, more preferably 15 minutes to 4 hours.
Further, although the pressure in the step of foaming the foamable resin composition can be selected as appropriate, foaming is preferably performed under atmospheric pressure.

In the method for producing a polyurea resin foam according to the present invention, before the step of foaming the foamable resin composition, the amine compound (a1) is brought into contact with a gas containing carbon dioxide. It is preferable to further include a step of reacting the reaction product with carbon dioxide to obtain the reactant (a2).

The gas containing carbon dioxide may be carbon dioxide alone or a mixture of carbon dioxide and an inert gas. It is convenient and preferable to use air as the gas containing carbon dioxide. Here, the term "inert gas" refers to a gas that does not affect the reaction when obtaining a polyurea resin foam, which will be described later.
The carbon dioxide concentration of the gas containing carbon dioxide is determined by the step of reacting the amine compound (a1) and carbon dioxide to obtain the reactant (a2) by contacting the gas with a carbon dioxide concentration of 0.01% by volume or more and 10% by volume or less. It is preferable to further include.
The carbon dioxide concentration is preferably 0.01 volume% or more, more preferably 0.02 volume% or more, still more preferably 0.03 volume% or more, and preferably 10 volume% or less. It is more preferably 5% by volume or less, still more preferably 1% by volume or less, even more preferably 0.5% by volume or less, even more preferably 0.1% by volume or less. Moreover, it is more preferable that the gas having a carbon dioxide concentration of 0.01% by volume or more and 10% by volume or less is air.

There are no restrictions on the method of bringing the amine compound (a1) into contact with a gas containing carbon dioxide, but the mass of the amine compound (a1) is brought into contact with a gas containing carbon dioxide at 30°C or less while stirring or shaking. It is preferable to preserve it until the rate of increase falls within the desired range. Although there is no restriction on the pressure at which the amine compound (a1) is brought into contact with a gas containing carbon dioxide, it is preferably stored under atmospheric pressure or under increased pressure, and more preferably stored under atmospheric pressure.

The reaction product (a2) of the amine compound (a1) and carbon dioxide preferably contains at least one selected from carbamic acid, carbamate, carbonate, and hydrogen carbonate.

Hereinafter, the present invention will be explained with reference to Examples, but the present invention is not limited to the scope of the Examples. In this example, various measurements were performed by the following methods.

(Acid dissociation constant (pKa) of amine compound)
The acid dissociation constant of the amine compound was determined by the following measurement method.
(1) 0.2 g of an amine compound was dissolved in 30 mL of purified water.
(2) The solution obtained in (1) above was titrated with a 0.1 N perchloric acid-acetic acid solution using an automatic potentiometric titrator (manufactured by Kyoto Electronics Industry Co., Ltd., AT-610). The dissociation constant (pKa) was calculated.
Note that the temperature during measurement was 25±2°C.

(Amine value of amine compound)
The amine value was measured by the following measuring method according to JIS K7237-1995.
(1) 0.1 g of an amine compound was dissolved in 20 mL of acetic acid.
(2) The solution obtained in (1) above was titrated with a 0.1 N perchloric acid-acetic acid solution using an automatic potentiometric titrator (manufactured by Kyoto Electronics Industry Co., Ltd., AT-610) to obtain amines. The value was calculated.
Note that ethylenediamine cannot be measured under the above measurement conditions, so calculated values are shown in Table 1.

(Maximum endothermic temperature of amine compound)
DTA measurement was performed on the amine compound as follows, and the maximum endothermic temperature of the amine compound was measured. First, an amine compound was measured using a differential thermal gravimeter (product name: DTG-60, manufactured by Shimadzu Corporation) under the conditions of a measurement temperature range of 23 to 350°C, a heating rate of 10°C/min, and a nitrogen atmosphere. Differential scanning calorimetry was performed using From the DTA curve thus obtained, the temperature at which the amount of endotherm due to volatilization of the amine compound becomes maximum was calculated, and this temperature was defined as the maximum endothermic temperature of the amine compound.

(Maximum carbon dioxide (CO ₂ ) dissociation temperature of amine compound)
A carbon dioxide concentration meter and a petri dish were placed in a desiccator (inner dimensions: 370 mm x 260 mm x 272 mm) that could be opened and closed. Thereafter, the amine compound (5 mmol) was added to the petri dish in the desiccator, the door was immediately closed, and the amine compound was left in the desiccator in an air environment of 23° C. and 50% RH for 24 hours. Note that the initial concentration of carbon dioxide was adjusted to about 400 ppm.
Next, the amine compound was taken out from the desiccator to obtain an amine compound that had absorbed carbon dioxide. The amine compound that had absorbed carbon dioxide was subjected to DSC measurement as follows, and the carbon dioxide maximum dissociation temperature of the amine compound was measured. First, an amine compound was measured using a differential thermal gravimeter (product name: DTG-60, manufactured by Shimadzu Corporation) under the conditions of a measurement temperature range of 23 to 250°C, a heating rate of 10°C/min, and a nitrogen atmosphere. Differential scanning calorimetry was performed using From the DSC curve thus obtained, the temperature at which the amount of heat absorbed due to the desorption of carbon dioxide was maximized was calculated, and this temperature was defined as the maximum carbon dioxide dissociation temperature of the amine compound.

(Moisture content of foaming agent and composition of foaming agent)
The water content and the composition of the blowing agents manufactured in Examples and Comparative Examples were determined using an organic trace element analyzer (Microcoder JM10, manufactured by J Science Lab Co., Ltd. (Examples 1 and 2 and Comparative Example 2) or Measurement was performed using Yanaco CHN Coder MT-5, manufactured by Yanaco Technical Science Co., Ltd. (Examples 3 and 4 and Comparative Examples 1, 3, and 4).

(Evaluation of foamability)
The foamability of the foamable resin composition was evaluated based on the volume increase rate (fold, expansion ratio) of the polyurea resin foam. The volume increase rate is the thickness after foaming divided by the thickness before foaming when foaming is performed in a rectangular parallelepiped container with a fixed bottom shape (bottom area). It means that the larger the volume increase rate is, the better the foamability is.

In the Examples, the following amine compounds and polyisocyanate compounds were used.

(amine compound)
MXDA: metaxylylene diamine (manufactured by Mitsubishi Gas Chemical Co., Ltd.)
1,3-BAC: 1,3-bis(aminomethyl)cyclohexane (manufactured by Mitsubishi Gas Chemical Co., Ltd.)
Ethylenediamine: Ethylenediamine (manufactured by Tokyo Chemical Industry Co., Ltd.)

(Polyisocyanate compound)
IPDI: Isophorone diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)
MDI: 4,4'-diphenylmethane diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)
HDI: 1,6-hexamethylene diisocyanate (manufactured by Tokyo Chemical Industry Co., Ltd.)

Example 1
(1) Production of blowing agent (absorption of carbon dioxide into amine compound)
1,3-BAC, which is an amine compound, was placed in a container and allowed to stand for one week in an air environment of 23° C. and 50% RH. As a result, 1,3-BAC and carbon dioxide in the air were reacted to obtain a blowing agent (carbonate of 1,3-BAC). Here, in order to suppress reaction unevenness, the container containing the amine compound was shaken as appropriate to prevent unreacted 1,3-BAC from forming.
Next, the mass increase of 1,3-BAC was measured, and the mass increase rate of the amine compound was calculated from the following formula.
Mass increase rate of amine compound [mass%] = 100 x mass increase of amine compound (g) / (initial mass of amine compound (g) + mass increase of amine compound (g))

(2) Manufacture of foamable resin composition IPDI, which is a polyisocyanate compound, was added to the foaming agent (carbonate of 1,3-BAC) and stirred and mixed for 2 minutes to obtain a foamable resin composition. The amounts of the blowing agent and IPDI were such that the molar ratio of the number of amino groups in 1,3-BAC constituting the blowing agent/the number of isocyanate groups in IPDI was 1/1.

(3) Production of polyurea resin foam The foamable resin composition obtained in (2) was placed in a rectangular parallelepiped mold with a bottom surface of 12 cm x 12 cm so that the thickness was approximately 3 mm, and a hot air dryer was used. The foamable resin composition was cured and foamed by heating at a heating temperature of 150° C. and a heating time of 30 minutes. Thereby, a polyurea resin foam was obtained. Furthermore, it was confirmed by visual inspection that a foamed structure was formed in the obtained polyurea resin foam. Furthermore, the foamability of the obtained polyurea resin foam was evaluated. The results obtained are shown in Table 1.

Examples 2-3 and Comparative Examples 1-2
Polyurea resin foams were obtained in the same manner as in Example 1, except that the types of amine compound and polyisocyanate compound were changed to those shown in Table 1.
It was confirmed by visual inspection that a foamed structure was formed in the obtained polyurea resin foam. Furthermore, the foamability of the obtained polyurea resin foam was evaluated. The results obtained are shown in Table 1.

(Study of absorption time of carbon dioxide into amine compound)
Examples 4-5
Polyurea resin foams were obtained in the same manner as in Example 1, except that the types of amine compound and polyisocyanate compound in Example 1 were changed to those shown in Table 2.
It was confirmed by visual inspection that a foamed structure was formed in the obtained polyurea resin foam. Furthermore, the foamability of the obtained polyurea resin foam was evaluated. The results obtained are shown in Table 2.

Examples 6-7
In Examples 4 and 5, polyurea was prepared in the same manner as in Examples 4 and 5, except that the standing time in (1) production of a blowing agent (absorption of carbon dioxide into an amine compound) was changed from 1 week to 10 weeks. Each resin foam was obtained.
It was confirmed by visual inspection that a foamed structure was formed in the obtained polyurea resin foam. Furthermore, the foamability of the obtained polyurea resin foam was evaluated. The results obtained are shown in Table 2.
The results of Examples 4 to 7 show that foaming properties are improved by allowing a sufficient amount of time for the amine compound to be in contact with air (carbon dioxide absorption time).

From Table 1, it can be seen that according to the blowing agents and foamable resin compositions of Examples, polyurea resin foams with improved foamability can be produced without using conventional blowing agents that have a large environmental impact. Furthermore, the blowing agent and foamable resin composition of the Examples can be manufactured by absorbing carbon dioxide in the environment, which also contributes to reducing the environmental load.

Claims

A blowing agent for obtaining a polyurea resin foam containing polyurea having a repeating unit represented by the following general formula (I),
A blowing agent containing a reaction product (a2) of a cyclic amine compound (a1) and carbon dioxide.

(In formula (I), R 1 is a divalent hydrocarbon group having a cyclic structure that may have a substituent, and R 2 is a divalent hydrocarbon group that may have a substituent. It is a hydrogen group.)
When the cyclic amine compound (a1) is allowed to stand for one week in an air environment of 23° C. and 50% RH, the mass increase rate of the cyclic amine compound (a1) calculated by the following formula is 10% by mass or more 50 The blowing agent according to claim 1, which is not more than % by mass.
Mass increase rate [mass%] of cyclic amine compound (a1) = 100 x mass increase amount (g) of cyclic amine compound (a1) / (mass (g) of cyclic amine compound (a1) + cyclic amine compound (a1) mass increase (g))
The blowing agent according to claim 1 or 2, wherein the cyclic amine compound (a1) has an amino group bonded to a primary carbon atom.
The blowing agent according to any one of claims 1 to 3, wherein the cyclic structure of the cyclic amine compound (a1) contains at least one type selected from a 5-membered ring and a 6-membered ring.
The blowing agent according to any one of claims 1 to 4, wherein the number of amino groups in the cyclic amine compound (a1) is 2 or more and 6 or less.
The cyclic amine compound (a1) contains at least one selected from the group consisting of xylylenediamine and its derivatives, bis(aminomethyl)cyclohexane and its derivatives, limonenediamine and its derivatives, and isophoronediamine and its derivatives. The blowing agent according to any one of items 1 to 5.
The blowing agent according to any one of claims 1 to 6, wherein the amount of water in the reactant (a2) is 50% by mass or less.
Any one of claims 1 to 7, wherein the molar ratio of the moiety derived from the cyclic amine compound (a1) and the moiety derived from carbon dioxide [cyclic amine compound (a1)/carbon dioxide] is 70/30 to 30/70. Foaming agent as described.
The blowing agent according to any one of claims 1 to 8, wherein the content of the repeating unit represented by the general formula (I) in the polyurea is 50% by mass or more.
Claim 1: Produced by a method in which the cyclic amine compound (a1) is brought into contact with a gas having a carbon dioxide concentration of 0.01% by volume or more and 10% by volume or less to react the cyclic amine compound (a1) with carbon dioxide. The blowing agent according to any one of 9 to 9.
A foamable resin composition for obtaining a polyurea resin foam, the composition comprising:
A foamable resin composition comprising the foaming agent (A) according to any one of claims 1 to 10 and a polyisocyanate compound (B).
The foamable resin composition according to claim 11, wherein the polyisocyanate compound (B) includes a compound having two or more isocyanate groups.
The foamable resin composition according to claim 11 or 12, wherein the content of a blowing agent other than the blowing agent (A) is 5% by mass or less.
The content of the blowing agent (A) in the foamable resin composition is determined by the ratio of the number of amino groups in the blowing agent (A) to the number of isocyanate groups in the polyisocyanate compound (B) (number of amino groups/the number of isocyanate groups). The foamable resin composition according to any one of claims 11 to 13, wherein the foamable resin composition has an amount of 0.5 or more and 1.5 or less.
A claim in which the polyisocyanate compound (B) is at least one selected from the group consisting of isophorone diisocyanate (IPDI), 1,6-hexamethylene diisocyanate (HDI), and 4,4'-diphenylmethane diisocyanate (MDI). 15. The foamable resin composition according to any one of 11 to 14.
A polyurea resin foam obtained by foam-molding the foamable resin composition according to any one of claims 11 to 15.
A method for producing a polyurea resin foam, comprising the step of foam-molding the foamable resin composition according to any one of claims 11 to 15.